It is common in industrial settings to employ overhead conveyor systems to move articles from point to point, as may be required in many industrial applications. These overhead conveyor systems typically include an overhead track system, several trolley assemblies, a conveyor chain to join and drive the trolley assemblies along the track and turn wheel assemblies to guide the conveyor chain. The trolley assemblies have attached hangers which extend below the track to transport the desired articles along the track.
The typical overhead conveyor systems described above, while useful, suffer from several disadvantages. First, the various components of the trolley wheel systems require significant amounts of maintenance. If the components of the trolley wheel systems are not maintained properly, the system will not operate at optimal levels. As one example of required maintenance, most trolley wheel assemblies require that additional lubrication be added from time to time (the additional lubrication itself presents some problems as discussed below). The lubricant helps decrease component part wear, at least partially, by decreasing the coefficient of friction associated with the operation on the conveyor system. If the addition of lubrication is ignored, the coefficient of friction will increase, placing increased stress on the component parts, which may lead to system failure. For example, if lubrication maintenance is not performed, the friction generated by the trolley assemblies will increase. This increases the resistance the conveyor system encounters and places stress on the components of the conveyor system, as well as increasing the energy required to operate the conveyor system. Likely results will be an increase in the chain pitch (or chain length) and/or premature chain failure. If the chain pitch is increased enough, the timing of the system may be impacted, causing defects in the associated industrial processes. In either case, the conveyor system and its associated industrial process must be stopped so that sections of chain can be removed to restore the original pitch to the chain or a new chain installed. The maintenance problems are exacerbated when the trolley wheel systems are required to function in harsh environments. In these situations, the maintenance requirements for trolley wheel systems may be further increased.
As stated above, adding additional lubricants to overhead conveyor systems presents significant problems. The additional lubrication will drop from the trolley wheel system during operation, and potentially contaminate the articles carried by the trolley wheel system. The added lubricant may mix with rust that has developed on the components of the conveyor system as well, bringing additional contaminates into contact with the articles carried by the system. This phenomenon is so common in some industries (such as the poultry processing industry), it is known as “rail dust,” which is sometimes referred to as “black rain.”
Finally, the individual components of the conveyor systems are not engineered as a unit to maximize the operation and longevity of the system. As discussed above, increased friction, caused by the design of the individual components and inadequate lubrication, may cause changes in the chain pitch. Solutions to this problem have been to design trolley wheel assemblies with improved lubrication properties. However, these solutions only address part of the underlying issue. For example, a conveyor chain with improved resistance to changes in pitch could be combined with a trolley wheel assembly with improved properties, to improve the operation of the conveyor system as a whole.
Such a synergistic approach has been lacking. The present disclosure provides such an approach to describe an improved overhead conveyor system and the component parts thereof.